M,Mg0=40g/mol
M,Mg= 24g/mol
Vm= 22,4l/mol
1mol.........0,5mol.........1mol
Mg + 1/2 O2---------> MgO
24g.........0,5x22,4 L........40g
3g................x..................y
x= V,O2=1,4 l
y= m,MgO= 5g
1mol......................1mol
MgO + H2O---> Mg(OH)2
40g.....................(24+32+2)g
5g........................m=.................................calculeaza !!!!!